Pull-out switch



J1me 4 N. 4. SCHMEILIG ETAL 2,472,268

PULL-OUT SWITCH Filed July 5, 1945 I 2 Sheets-Sheet 1 June 7, 1949'.

N-.- J. SCHMELIG ETAL PULL-OUT SWITCH Filed July 5, 1945 2 Sheets-Sheet 2 )V/CHOLAS J.

Patented June 7, 1949 PULL-OUT SWITCH .Nicholas v.I. Schmelig and Floyd S. Green, St. Louis, Mo., assignors to Frank Adam Electric Company, St. Louis, Mo., a corporation ofMissouri Application July 5, 1945, Serial No. 603,388

11 Claims. 1

This invention relates to :aswitch of the hinged cover pull out type.

It is an object of this .invention to provide an improved switch of the above mentioned type.

It is another object .of this invention to provide such a switch which can .be mounted either individually in a separate .box, or assembled .on a mounting frame in a cabinet with other units of either the same or other types.

It is also an object of this invention to provide means for extinguishingthe are when the circuit is opened.

Further objects of the invention will appear from the following description and accompanying drawings.

Referring now to the drawings:

Fig. 1 is a longitudinal cross-sectional view of the switch provided'by this invention, in the on position. It is taken along line I-l of Fig. 4.

Fig. 2 is a similar view with the switch in the off position.

Fig. 3 is a plan view of the inside .of the door of the switch.

Fig. 4 is a plan view of the switch with the cover removed.

Figures 5, 6 and '7 are enlarged, partial, crosssectional views of the contacts in closed, almost open, and open positions respectively.

The switch, as shown, may be applied to a suitable enclosure or mounting .frame.

The switch .is mounted on a frame with a back 10 and two side walls H. At the end, the side walls are supported by specially formed angles [2 which support a special hinge at one end of the frame and a latch at the other end of the frame. The ends of the enclosure are arranged for an insulating barrier which closes up the end and will be describedin detail later.

The switch enclosure .is furnished with .a door M.

The switch base I6 is mounted on the back of the frame and is made of specially designed molded insulating material provided with the proper recesses and formations to accommodate the line terminal connections, and the line and load switch contacts. The base is also provided with a recess to accommodate the movable barrier which acts as a means to extinguish the are formed between the line and load contacts during the opening of the switch. This barrier will be later described.

This specially molded insulating base may-be formed for one or more poles as is desired. It should be noted that the :make and break connections provide a double break of the The line contact 20 may be secured by a terminal 24 as shown. The load switch contact '22 is continued to connect with a fuse connection 18. The fuse connection [8 is spaced to allow sufiicient clearance for the switch blade when it :is positioned as shown in Fig. 2. When desired, a load terminal connection may be provided instead of the fuse connection I8.

A block of insulating material 23 secured on the back It serves as a base for the load fuse clips 30. The clips 30 may be provided with .a conducting strip 32 to connect to load terminal 34. 3'6 is a fuse.

An arc extinguishing sliding barrier 38 is positioned between the line and load contacts in the recess provided .for it. A spring 42 is positioned behind th sliding barrier and arranged to move the barrier between the line and load contacts when the switch blade on the cover, later to be described, is removed from between the contacts.

The switch door It has a hinge at one end and a latch at the other, as well as a handle to operate the door to open or closed position.

A slidable mounting plate 4'! is supported on the door by studs 48 provided with enlarged heads. These studs operate in slots 50 of the mounting plate. A block of insulation 46 is secured to the mounting plate 41 by any suitable means. This block of insulating material may be molded to accommodate switch blades 52. These switch blades are arranged to co-operate with the fixed line and load contacts 20 and 22 previously described. A handle 54 is provided on the door. Only one of the studs 48 is visible in the drawings since the other is located under insulating block 46.

A snap action linkage is provided for the mounting plate 47 by spring 56 and toggle 5B which is pivoted at one end as shown, and is positioned in an opening 60 at the other end. The opening 60 may be formed in a bent over formation 62 of the plate 41.

The mounting plate 4! with the switch contacts mounted thereon, may thus be moved towards the latch end of the door for the on position and towards the hinge end for the ofP position. In the embodiment shown, the door of the switch must first be opened before the plate 41 can be shifted by hand. It is obvious of course, that a knob could be extended through the door .to accomplish this purpose from the outside of the door if desired.

It should be noted that the switch blades are specially formed so that any burning caused by the arcing upon making or breaking the circuit,

will appear near the tip of these switch blade contacts. This can be seen by inspection of Figs. 5, 6 and '7. It should also be noted that the switch blades are so positioned that the arcin and burning at the make and break points on the line and load contacts occur at a point other than the surfaces which are used for the continuous current carrying position of the switch. This can also be seen by comparison of Figs. 5, 6 and '7.

It should be noted that the spring and toggle 56 and 58 provide for a positive positioning for both the on and off" positions of the switch blades. This snap action positioning prevents the switch blades from assuming an intermediate position that might damage the switch.

The insulating barrier 84 is provided as shown and may be fastened as shown to the angle.

A snap catch 66 may be provided on the door if desired.

Under operating conditions the circuit is closed by the switch blades when the door and mounting plate are in the position shown in Fig. 1. If it is desired to break the circuit it is necessary to open the door by means of the handle 54.

. Opening the door disengages the switch blades 52 from the line and load contacts 20 and 22, thereby opening the circuit. The barrier lfi, under action of spring 42, immediately follows the blade 52 out beyond the contacts 20 and 22 and efficiently snuffs out the arc.

It should be noted that the insulating barrier 64 is positioned with respect to the molded insulating base it to prevent contact with live line connections 20 and 24. This makes it impossible for a person to come into contact with the live line connections of the switch.

If it should be desired to close the door and yet keep the circuit open, it is necessary to shift the .mounting plate 41 into the o position shown in Fig. 2 and then to close the door. The circuit is now open while the door is closed.

By changing the spacing between the insulating blocks [6 and 28 it is possible to change the switch to accommodate different voltages and capacities of fuses with the same parts. In addition to the several advantages which have already been pointed out in connection with the description of the invention, it should be noted that when the switch blades are in the full on position that the tips come together and make it possible to get sufficient pressure on the line and -load contacts, and yet allow sufiicient resilience.

These tips separate when the circuit is broken and thus provide a. double break which greatly increases the interrupting capacity of the switch.

A three pole switch is shown in the drawings although it is obvious that various numbers of poles may be used.

The insulating block i6 has a formation 65 which acts as a guide for the switch blades in entering for the on position.

The switch must be used in connection with an enclosure or mounting frame which provides a fixed and accurate distance between door and back. If this is not done the switch blades will not properly contact the line and load contacts. While one embodiment of the switch has been shown, it will be apparent to those skilled in the art that various changes may be made therein without departing from the invention as defined by the following claims.

, We claim:

1. An electric switch comprising a casing having a door and a back, a base of molded insulating material on said back, a line and a load contact, a line terminal secured to said line contact, said line and load contacts being oppositely disposed and spaced from each other, a recess in said base adapted to accommodate said line and load contacts, a. slidable mounting plate on said door. a switch blade mounted upon said plate, said switch blade being of substantial U-shape, said slidable mounting plate having an on and an off position, the ofi position locating the switch blade so that no contact is made between the line and load contacts when the door is closed, and the on position locating the switch blade so that it moves between the line and load contacts when the door is closed, the U-shaped switch blade being provided with ends which abut When inserted between the line and load contacts.

2. An electric switch comprising a casing having a door and a back, a base of molded insulating material on said back, a line and a load contact, a line terminal secured to said line contact, said line and load contacts bein oppositel disposed and spaced from each other, a recess in said base adapted to accommodate said line and load contacts, a slidable mounting plate on said door, a switch blade mounted upon said plate, said switch blade being of substantial U-shape, having bulges near the open ends thereof, and being formed so that when it is inserted between the line and load contacts the "ends thereof engage each other and cause the bulges to exert pressure on the line and load contacts, said slidable mounting plate having an on and off" position, the o position locating the switch blade so that no contact is made between the line and load contacts when the door is closed, and the on position locating the switch blade so that it moves between the line and load contacts when the door is closed, the switch blade being so designed that the ends thereof part just before it is removed from between the line and load contacts.

3. An electric switch comprising a casing having a door and a back, a base of molded insulating material on said back, a line and a load contact, a line terminal secured to said line contact, said line and load contacts being oppositely disposed and spaced from each other, a recess in said base adapted to accommodate said line and load contacts, a slidable mounting plate on said door, a switch blade mounted upon said plate, said switch blade being of substantial U-shape, having bulges near the open ends thereof, and being formed so that when it is inserted between the line and load contacts the ends thereof engage each other and cause the bulges to exert pressure on the line and load contacts, said slidable mounting plate having an on and oil position, the off position locating the switch blade so that no contact is made between the line and load contacts when the door is closed, and the on position locating the switch blade so that it moves between the line and load contacts when the door is closed.

' 4. An electric switch comprising a casing having a door and a back, an insulating base on the back and at one end thereof, oppositely disposed line and load contacts, a line terminal secured to said line contacts, a recess in said base, said recess being shaped to accommodate said line and load contacts, an insulating barrier positioned in said recess and spring biased from the bottom thereof to move between said line and load contacts, said lead contacts being electrically connected to a fuse-receiving terminal, an insulating open and a closed circuit position, space being provided on said base between the fuse terminal receiving member and the walls of the recess'enclosing theline and load contacts for the positioning of the switch blade when the door is closed and the blades are in the off position.

5. An electric switch comprising a casing having a door, side walls and a back, a, base of insulating material secured to the back at one end thereof, oppositely disposed line and load contacts secured to said base, a recess in said base arranged to accommodate said line and load contacts, a switch blade mounted on said door, means to move said switch blades from open to closed circuit position, or from closed to open circuit position, said switch blades being of substantial U-shape and arranged tov move between the line and load contacts when. the door of the switch is closed and the switch blades are in the closed circuit position, said switchblades being so formed that the open. ends thereof engage each other when the switch blade is inserted between the line and load contacts, thus causing the sides of the blades to exert pressure against the line and load contacts, a load terminal on said base, a space between said load terminals and the walls of said recess adapted to accommodate the switch blade when the door is closed and the switch blades are in the o position, the walls of said recess being sloped to form a guide for the entrance of the switch blades to a, position between the line and load contacts, the switch blade being designed so that the ends thereof part just'before it moves out from between the line and load contacts.

6. An electric switch comprising a casing having a door, side walls and a back, a base of insulating material secured to the back at one end thereof, oppositely disposed line and load contacts secured to said base, a recess in said base arranged to accommodate said line and load contacts, a switch blade mounted on said door, means to move said switch blades from open to closed circuit position, or from closed to open circuit position, said switch blades being of substantial U-shape and arranged to move between the line and load contacts when the door of the switch is closed and the switch blades are in the closed circuit position, said switch blades being so formed that the open ends thereof engage each other when the switch blade is inserted between the line and load contacts, thus causing the sides of the blades to exert pressure against the line and load conacts, a load terminal on said base, a, space between said load terminals and the walls of said recess adapted to accommodate the switch blade when the door is closed and the switch blades are in the o position, the walls of said recess being sloped to form a guide for the entrance of the switch blades to a position between the line and load contacts.

7. A switch comprising a casing having a door and a back, an insulating base secured to the back, said base being provided with a recess, a line contact located in said recess, an oppositely 6 disposed load contact-located in said recess, a line terminal secured to said line contact, an arc snuffing barrier of insulating material located at the bottom of said recess between said line and load contacts, means biasing said barrier to move up outof' the recess and between the line and load contacts, a switch blade on the door of said switch adapted to co-operate with said line and load contacts, said switch blade being of substantial- U-shape and provided with oppositely disposed bulges near the end thereof, said switch blades being formed so that when inserted betweenthe line and load contacts the ends of the U meet and force the bulges against the line and load contacts, movement of the switch blades between the line and load contacts serving to depress the arc snuffing barrier, the switch blades being so formed that upon movement from between the line and load contact the end of the U -shaped blade parts before contact between line and loadcontacts is broken.

8. A switch comprising a casing having a door and a back, aninsulating base secured to the back, said base being provided with a recess, a line contact located in said recess, an oppositely disposed load contact located in said recess, a line terminal secured to said line contact, an arc snuffing barrier of insulating material located at the bottom of said recess between said line and load contacts, means biasing said barrier to move up out of the recess and between the line and load contacts, a switch blade on the door of said switch adapted to co-operate with said line and load contacts, said switch blade being of substantial U-shape and provided with oppositely disposed bulges near the end thereof, said switch blades being formed so that when inserted between the line and load contacts the ends of the U meet and force the bulges against the line and load contacts, movement of the switch blades between the line and load contacts serving to depress the arc snuifing barrier.

9. A switch comprising a casing having a back and side walls, angles at the end of said switch extending between said side walls, a formation of insulating material secured to the back of said enclosure adjacent one end thereof, said formation being provided with recesses therein, a line contact located in one of said recesses and secured to said formation of insulating material, a load contact oppositely disposed to the line contact located in the same recess, a door supported by one of said angles, a slidable mounting plate secured to said door and adapted to slide into on and ofi positions, a spring and toggle linkage adapted to snap said movable plate from on to off or off to on positions, an insulating member secured on said mounting plate, a switch blade secured to said insulating member, said switch blade being of substantial U-shape and having a bulge near the open end thereof, said switch blade being so proportioned that when it is pushed between the line and load contacts its ends meet and cause the bulge to exert pressure on the line and load contacts, an insulating arc snufiing member located between the line and load contacts in a recess of the insulating formation and spring biased to move up out of the recess and between the line and load contacts, movement of the switch blade into position between the line and load contacts serving to depress said insulating arc snufiing member, movement of the mounting plate into the OE position being adapted to position the switch blade so that the closing of the door may be effected without closing the circuit to the line and load contact.

10. A switch comprising a casing having a back and side walls, angles at the end of said switch extending between said side walls, a formation of insulating material secured to the back of said enclosure adjacent one end thereof, said formation being provided with recesses therein, a line contact located in one of said recesses and secured to said formation of insulating material, a load contact oppositely disposed to the line contact located in the same recess, a door supported by one of said angles, a slidable mounting plate secured to said door and adapted to slide into on and off positions, an insulating member secured on said mounting plate, a switch blade secured to said insulating member, said switch blade being of substantial U-shape and having a bulge near the open end thereof, said switch blade being so proportioned that when it is pushed between the line and load contacts its ends meet and cause the bulge to exert pressure on the line and load contacts, an insulating arc snufi'ing member located between the line and load contacts in a recess of the insulating formation and spring biased to move up out of the recess and between the line and load contacts, movement of the switch blade into position between the line and load contacts serving to depress said insulating arc snufiing member, movement of the mounting plate into the off position being adapted to position the switch blade so that the closing of the door may be effected without closing the circuit to the line and load contact.

11. In an electric switch having a pair of spaced stationary contacts and a switch member insertable between said contacts to bridge the same, said switch member being U-shaped with legs resiliently yieldable toward and away from each other, portions of said legs having outer surfaces normally spaced further apart than the NICHOLAS J. SCHMELIG. FLOYD S. GREEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,233,062 Johansson July 10, 1917 1,755,612 Runsvold Apr. 22, 1930 2,124,275 Rowe July 19, 1938 2,152,283 Ruppel Mar. 28, 1939 2,191,501 Schmidt Feb. 27, 1940 2,319,906 Rowe May 25, 1943 2,324,047 Van Ryan July 13, 1943 

